What's Cool In Road Cycling

Dietary Supplements: Caveat Emptor

This week’s Tool Box opens up to reveal some truths, falses, and possible consequences about the plethora of “wonderous” nutritional supplements guaranteed to make you faster, stronger, better….

– By Stephen S. Cheung, Ph.D. –

At the start of each year for my introduction to exercise physiology course, I like to ask my students what burning question they have about exercise physiology that they really hope to get out of the course. The answers are always interesting and quite varied. The majority, like you, want to know how their body works and how to optimize its performance. However, one of the consistent themes revolves around wanting to know whether dietary supplements, from vitamins and protein powders to ergogenic supplements like creatine and caffeine, actually work. Given the massive marketing behind the billion dollar supplement industry and all the anecdotal hearsay, it’s very difficult sometimes to separate the physiological facts from the marketing hype. Therefore, I’ll spend this article outlining my own personal philosophy around supplements, then follow this up with future articles on specific supplements.

I’ll start off with my own philosophy. The industry may not want to hear it, but I am a BIG fan of proper training and nutrition, and not a believer at all in the majority of the available supplements. This was echoed by many sport nutritionists and researchers in a recent roundtable discussion on sport nutrition (1). The major alarm bells surrounding athletic supplements include:

1. Unlike medicines and drugs, which are closely regulated by governmental agencies like the FDA and Health Canada, there are NO regulations surrounding the testing of supplements. Medicines all have an extensive track record of scientifically rigourous testing to see whether it actually works as advertised and is safe. There are no requirements for the testing of any supplements, so you are only left with the promise of the company that the supplement actually works.

2. Following on the above, there is also no screening of supplements by any agencies. That means that you have no guarantees of the purity of the product, or even whether the ingredients on the label are correct! Worse yet, there is the high risk of contamination with substances not listed on the label, leading to the potential for positive drug tests or even allergic reactions. Remember Gilberto Simoni at the Giro this year and the cocaine-laced cough drops his Grandma brought back from South America? And how many times have you heard an athlete test positive and then blame it on the supplements they were taking?

3. Some supplements have the potential of serious side effects that you and even the scientific community may not be aware of. Again, this goes back to the constantly increasing number of supplements appearing on the market, coupled with the relative lack of scientific testing.

Please keep in mind that I’m not dissing all supplements or claiming that every company is dishonest. It’s just that this is an example of the ultimate free-enterprise system, and it is definitely buyer beware. The best defence is information, and I’ll try to arm you with that in future articles. If you have specific questions on particular supplements, please let me know.

1. Clarkson P, Coleman E, and Rosenbloom C. Risky dietary supplements. GSSI Sport Science Exchange Roundtable 48(13): 1-4, 2002.

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